Improvement in evaporators for salts



J. R. HOPKINS.

Evaporating Pain.

Patented ,Oct

N. PETERS. PlloXwLiVhugnphet. washingtqn. D4 C.

v UNITED STATES PATE T QrFIcE,

J. R. HOPKINS, OF AUBURN, NEW YORK.

IMPRdVEMENT IN EVAPORATORS FOR SALTS.

Specification forming part of Letters Patent No. 15,975, dated October 25 1856.

To all whom, it may concern Be it known that I, JOHN R. HorKINs, of Auburn, in the county of Cayuga and State of New York, have invented a new and Improved Apparatus for Evaporatin g Solutions, of which the .following is a full and accurate description, reference being had to the accompanying drawings, and to the letters of reference marked thereon.

A, Figure 1, is a close boiler, of copper, iron, or other metal, connected with a vat or reservoir, D, of wood, metal, or other substance, by metallic pipes B and 0, provided with gates or stop-cocks b and c. The vat D is divided by an inclined partition, F I G J, which extends on the same plane to the point K, and forms the bottom of the smaller and upper division. 1

The dotted lines J K and I 0 indicate the lower edges of triangular pieces fitted into op? posite corners, by which the form of the bottom is made to converge toward a small aperture through the lowest part thereof at N.v Between the apertures of the pipes 13 and 0, which terminate in the division, is fitted an inclined shelf, 0. (Shown by dotted lines be tween the triangular pieces L and M.) The lower and larger division ismarked P. It extends under and beyond the upper division, and is open at Q. Below this division is a small compartment or chamber, R, connected therewith by the pipe S, having a cock, 3, and a strainer or filter. (Shown by dots within and at the lowest point of division, 1?, about the aperture of the pipeS.) r

T, Fig. 2, is a vat or reservoir, of wood,

metal, or other substance, fitted to and designed, when in use, to sit immediately over the upper division of vat D, Fig. 1, and extends over the boiler A. It is elevatedabove in the drawings to show more distinctly the form of the upper division of vat D. The bottom of the vat T is constructed of a semicircular metallic plate, extending from end to end, with its concave side downward, and forming an arched space, which is divided by a vertical partition at G, all of which is shown by dotted lines. At the base of the larger division of this arched space, on each side, is an inclined conductor, V V, to carry off the water resulting from condensation of steam upon the semicircular metallic plate within this division. The steam remaining unconto the atmosphere by the pipe E, inserted through the top of this division.

The apparatus above described is designed for the evaporation of solutions whose solvent powers are increased by the application of heat and diminished by cooling.

In operating the part illustrated by Fig. 1, the gates or stop-cocks in the pipes are to be opened and the vat, boiler, and pipes charged with the solution, and kept charged above theaperture of the upper pipe so long as the operation is continued. The fire is then kindled, the solution contained in the boiler heated, and a current thereby produced, flowing through the boiler, pipes, and upper division or" the vat. This current is regulated by the stop-cocks in the pipes. The solvent capacity of the solution forming this current is alternatel y increased by heat while passing through the boiler and diminished by cooling while passing through the upper division of the vat, where its volume is expanded over a large surface, and the steam generated in the boiler is allowed to escape into the atmosphere, and where, after it is concentrated to saturation, its salts are necessarily precipitated. These salts are gathered by the converging or hopper-shaped bottom of this division to its lowest point, where they pass through a small aperture into the relatively cool and quiescent strata of the solution contained in the lower division of the vat, and an equivalent portion of the solution passes upward through the aperture into the'boiling current. lhese salts are to remain in the lower division of the vat until the crystals have attained thevdesired size, when they are to be withdrawn from the solution.

When solutions contain'several salts differing in solubility and specific gravity-some greater and others less than the one desired-- the salts of less solubility should be precipi tated from the solution in another vat before it is subjected to the operation above described. Salts of greater solubility and specific gravity impart the same qualities to their solutions, which, in a quiescent condition,

range themselves in strata corresponding to the relative specific gravity of their salts, and may be approximately separated by allowing ber may be removed and the chamber refilled as oftenas necessary without interruption to the evaporating operation in the upper division of the vat. L

When evaporation is conducted on a scale to render the utmost economy of fuel necessary-as in the manufacture of common salt, alum, &c.the vat described as Fig. 2 is to be placed over the boiler and the upper division of vat, Fig. 1. It is to be kept charged with the' brine or other solution, and a less rapid evaporation maintained by the application of the waste heat from thefurnace, and by condensation of the steam from the upper division of vat, Fig. 1,*upon the arched metallic plate, which forms the bottom of vat, Fig. 2, thereby concentrating the solution preparatory to its more vigorous evaporation in the boiler and vat below.

The above description of my apparatus and its mode of operation, it is believed, will enable any person skilled in the art to which it relates to construct the same, or modify its operation to any solution within the range of its design and adaptation. Some of the effects peculiar to this apparatus, and which consti 'tute its advantages over others heretofore in use, are: first, it enables the operator to regulate the increase of temperature in the volume of the solution forcing the current through the boiler and upper division of the vat by means of the stop-cocks in the connecting-pipes, and prevents the separation of steam or the deposit of the salts from the solution until carried by the current away from the heated metallic surfaces of the boiler, thus obviating the formation of corrosive and nonconducting incrustations thereon; second, it permits a rapid ebullition in a relatively small portion of the solution at the surface of the vat, while the lower and much larger portion remains relatively cool and quiescent, thereby economizing so much fuel as would otherwise be necessary to maintain a temperature in the the whole body of the solution sufficien't to produce an equal evaporation from the surface, and furnishing the most favorable conditions for the perfect crystallization of the salts depositing from the boiling current at the surface; third, it admits an approximate separation in solution of substances more soluble and heavier than the one desired in' the manner'already described, thus obviating the necessity of a periodical suspension of the evaporating process to discharge these substances which are continually accui'nulating in the mother solution.

What I claim as my invention, and desire to secure by Letters Patent, is

The apparatus for the evaporation of solutions whose solvent capacities are increased by application of heat and diminished by cooling, consisting of a close boiler, in combination with one or more vats or reservoirs, arranged substantiallyin the manner described.

JOHN R. HOPKINS.

Attcst:

H. H. BosTIoK, J. S. BRADBURN. 

